TWI432414B - Process for the carbonylation of dimethyl ether - Google Patents

Description

Method for carbonylation of dimethyl ether (2)

The present invention is related to a process for preparing methyl acetate by reacting dimethyl ether with carbon monoxide in the presence of a zeolite catalyst.

Methyl acetate is industrially used in petrochemical processes, particularly as a feedstock for the production of acetic acid and/or acetic anhydride.

Commercial production of acetic acid operates in a homogeneous liquid phase process wherein the carbonylation reaction is catalyzed by a Group VIII noble metal such as ruthenium or osmium and an alkyl iodide such as methyl iodide. The main disadvantage of this process is that the use of iodide can cause corrosion problems and problems associated with the separation of such products from the catalyst component from a single phase. Both of these disadvantages can be overcome if a non-homogeneous gas phase process using a solid catalyst without iodide can be developed.

EP-A-0 596 632 describes a vapor phase process for the carbonylation of methanol to produce acetic acid at higher temperatures and pressures in the presence of a modified mordenite catalyst.

WO 01/07393 describes a method for catalytically converting a feed comprising carbon monoxide and hydrogen to produce at least one of a mixture of alcohols, ethers and the like, and carbon monoxide with the alcohols, ethers At least one of a mixture of a class and a mixture thereof, in the presence of a catalyst selected from the group consisting of solid superacids, heteropolyacids, enamel clays, zeolites, and molecular sieves, is sufficient to produce an ester without a halide promoter A process in which at least one of a mixture of acids, acids, anhydrides, and the like is subjected to a reaction under temperature and pressure conditions. Of course However, it does not exemplify the use of a zeolite for catalyzing a carbonylation reaction.

WO 2005/105720 describes a process in the range of from 250 to 600 ° C and at a pressure in the range from 10 to 200 bar, with substantially no halogen and with a modified mordenite catalyst, by carbon monoxide An aliphatic alcohol or a reactive derivative thereof is carbonylated to produce a monocarboxylic acid and/or monoester or anhydride. It does not exemplify the dimethyl ether used as a feed.

WO 2006/121778 describes the production of a lower aliphatic carboxy group by carbonylation of a lower alkyl ether with carbon monoxide in the presence of a mordenite or ferrierite catalyst in the substantial absence of water. Process for lower alkyl esters of acid. According to this patent application, the carbonylation process is carried out at or below 250 ° C, preferably at about 150 to about 180 ° C to minimize the formation of by-products.

Based on the above-mentioned prior art, there is still a need for a non-homogeneous gas phase process for the production of methyl acetate from dimethyl ether using a zeolite catalyst substantially free of water, which is superior to other carbonylation. The reactants act as a feedstock.

It has now been found that if the carbonylation process is carried out at temperatures ranging from 240 ° C to 350 ° C and in the presence of hydrogen, it can achieve better productivity and/or catalyst stability. The effect of hydrogen on productivity and/or catalyst stability over a range of temperatures between 240 ° C and 350 ° C can be further enhanced by the presence of one or more promoter metals on the zeolite.

Accordingly, the present invention provides a process for producing methyl acetate, which The process comprises the effect of carbonylating a dimethyl ether feed with carbon monoxide in the presence of a zeolitic catalyst effective for the carbonylation, wherein the carbonylation is at 240 ° C in the substantial absence of water. The temperature in the range of up to 350 ° C is carried out in the presence of hydrogen.

The present invention solves the above-defined problems by operating the process at elevated temperatures and in the presence of hydrogen to achieve good productivity in the formation of methyl acetate products. A hairline that can be achieved by using hydrogen at high temperatures is surprising because it is mentioned in the results described in the above-mentioned WO 2006/121778 that it is expected that the presence of hydrogen will not or will only be The rate of formation of methyl acetate in the zeolite-catalyzed dimethyl ether carbonylation process has a very small effect.

The dimethyl ether used as a feed to the process of the present invention may be a substantially pure dimethyl ether. In commercial practice, dimethyl ether is produced by catalytic conversion of a synthesis gas (a mixture of hydrogen and carbon monoxide) on a methanol synthesis and methanol dehydration catalyst. This catalytic conversion produces a product which is primarily dimethyl ether, but it may also contain some methanol. In the process of the present invention, the dimethyl ether feed may contain a small amount of methanol as long as the methanol content of the feed is not large enough to inhibit the carbonylation of dimethyl ether to the methyl acetate product. It has been found that 5 wt% or less (e.g., 1 wt%) of methanol can be tolerated in the dimethyl ether feed.

Suitably, the dimethyl ether is present in the feed in a concentration ranging from 0.1 to 20 mole percent based on the total feed amount (including the recycle), for example from 1.5 moles to 20 moles. % or 1.5% to 10% by mole, for example 1.5% to 5% by mole.

The carbon monoxide can be, for example, typically provided by an industrial gas supplier. The carbon monoxide supplied is essentially pure carbon monoxide, or it may contain impurities that do not interfere with the conversion of dimethyl ether to methyl acetate, such as nitrogen, helium, argon, methane and/or carbon dioxide.

The process of the present invention is carried out in the presence of hydrogen. The hydrogen may be fed as it enters the separate feed stream of the carbonylation reactor, or it may be fed in combination with, for example, carbon monoxide. The mixture of hydrogen and carbon monoxide is commercially produced by the recombination of hydrocarbon vapors and the partial oxidation of hydrocarbons. These mixtures are generally referred to as synthesis gases. The syngas system primarily contains carbon monoxide and hydrogen, but it may also contain small amounts of carbon dioxide.

Suitably, the molar ratio of carbon monoxide:hydrogen may range from 1:3 to 15:1, such as from 1:1 to 10:1, for example, from 1:1 to 4:1.

The molar ratio of the carbon monoxide to the upper dimethyl ether is suitably in the range of 1:1 to 99:1, for example 2:1 to 60:1.

The zeolite catalyst can be any zeolite which catalyzes the carbonylation of dimethyl ether with carbon monoxide to produce methyl acetate.

Zeolite can be acquired from commercial sources, generally Na zeolites for the system, NH ₄ form or H- form. The NH ₄ form can be converted to an acid (H-form) by known techniques such as high temperature calcination. The Na form can first be converted to an NH ₄ form by ion exchange with an ammonium salt such as ammonium nitrate and then converted to an acid (H-form). Alternatively, the zeolite can be synthesized using known techniques.

The zeolite comprises a channel system interconnected with other channel systems or cavities, such as side pockets or cage structures. The ring structure is usually 12-member ring, 10-member ring or 8-member ring. A zeolite may have rings of different sizes. The zeolites useful in the present invention preferably comprise at least one channel defined by an 8-membered ring. Most preferably, the 8-member ring channel is interconnected with at least one channel defined by a 10 and/or 12-member ring. The window size of the channel systems should be sufficient for the reactants dimethyl ether and carbon monoxide molecules to diffuse freely into and out of the zeolite framework. Suitably, the window size of an 8-member ring channel can be at least 2.5 x 3.6 angstroms. The Atlas of Zeolite Framework Types (C. Baerlocher, WM Meier, DHOlson, 5th ed. Elsevier, Amsterdam, 2001) and its web version (http://www.iza-structure.org/databases/) , is a brief description of the surface texture and structural details of the zeolite framework, including the type of ring structure that is present in a zeolite and the size of the channels defined by each ring type. Examples of zeolites suitable for use in the present invention include zeolites of the architectural type MOR, such as mordenite, FER such as ferrierite, such as OFF of potassium zeolite, and GME such as sodium chabazite.

For the process of the present invention, the zeolite preferably has a ratio of at least 5 to aluminum and preferably less than or equal to 100, such as in the range of from 7 to 40, for example. It is 10 to 30. When the aluminum atom is replaced by a structural modification element such as gallium, the ratio of the 矽:X ₂ O ₃ (where X is a trivalent element such as aluminum, gallium, iron, and/or boron) is at least 5 Preferably, it is less than or equal to 100, for example in the range of from 7 to 40, for example from 10 to 30.

Preferably, the zeolite used in the present invention has one or more metals such as copper, silver, nickel, ruthenium, rhodium, platinum, palladium or cobalt and mixtures thereof.

In a specific embodiment of the invention, the zeolite catalyst is a mordenite. The mordenite may be used in the form of an acid (H-mordenite), or it may optionally be ion exchanged or loaded into one of, for example, copper, silver, nickel, ruthenium, rhodium, platinum, palladium or cobalt. Or more metal.

The amount of metal loading on a zeolite (for example, mordenite) can be expressed by the ratio of metal loading, which is the ratio per gram atom of aluminum in the mordenite. The number of grams of metal. The metal loading can also be expressed as a percentage of the molar relative to the aluminum in the mordenite by the following relationship: mol% metal = (gram atom metal / gram atom aluminum) x 100

Thus, for example, a loading of 0.55 gram atom of copper per gram atom of the mordenite is equal to a copper loading of 55 mol% relative to the aluminum in the glazing.

Suitably, the metal loading may be in the range of from 1 to 200 mole % relative to the aluminum system, for example, 40 to 120 mole %, 50 to 120 mole %, such as 50 Up to 110% by mole or 55 to 120% by mole, for example 55 to 110% by mole.

In addition to the bismuth and aluminum atoms, the mordenite framework may contain additional trivalent elements such as boron, gallium and/or iron.

When the mordenite contains at least one or more trivalent structural elements, the metal loading amount in the mordenite can be expressed by a metal loading ratio, the loading ratio being in the mordenite The number of gram atoms of the metal per gram atom of the total trivalent element. The metal loading amount can also be expressed as a relative to the mordenite by the following relationship The molar percentage loading of the total trivalent element in the middle: Moer % metal = (gram atom metal / total trivalent element gram atom number) × 100

Since the carbonylation reaction is carried out substantially without moisture, the zeolite catalyst is preferably dried prior to use. The zeolite can be dried, for example, by heating to a temperature of from 400 to 500 °C.

The zeolite catalyst is preferably activated immediately prior to use by heating the zeolite for at least one hour at a higher temperature under flowing nitrogen, carbon monoxide, hydrogen or a mixture thereof.

The process is carried out in the case of substantially anhydrous (i.e., substantially free of water). The carbonylation of dimethyl ether to methyl acetate does not produce moisture at the reaction site. Moisture has been found to inhibit the carbonylation of dimethyl ether to methyl acetate. Therefore, in the process of the present invention, moisture will be maintained as low as possible. To achieve this goal, the dimethyl ether and carbon monoxide reactants (and catalyst) are preferably dried prior to introduction into the process. However, it may be able to tolerate a small amount of water without adversely affecting the formation of methyl acetate. Suitably, the dimethyl ether may comprise moisture in an amount of 2.5 wt% or less (e.g., 2.4 wt% or less, for example, 0.5 wt% or less).

The process of the present invention is carried out at a temperature ranging from 240 ° C to 350 ° C. Suitably, the temperature may be in the range of from 250 to 350 °C, such as from 275 to 350 °C, for example from 275 to 325 °C.

The process of the present invention can be carried out at a total pressure in the range of from 1 to 100 barg. Suitably, the pressure can be in the range of from 10 barg to 100 barg, for example from 10 to 80 barg, for example from 30 to 80 barg Or 30 barg to 100 barg.

The hydrogen partial pressure is suitably in the range of from 0.1 to 50 barg, for example from 3 to 30 barg, for example from 5 to 25 barg.

The partial pressure of carbon monoxide should be sufficient to allow the production of the methyl acetate product, but suitably in the range of from 0.1 to 50 barg.

The gas hourly space velocity (GHSV) is suitably in the range of 500 to 40,000 h ^-1 , such as 2000 to 20,000 h ^-1 .

The process of the present invention is suitably carried out by passing dimethyl ether vapor, hydrogen and carbon monoxide through a fixed or liquid bed of the zeolite catalyst maintained at a necessary temperature.

Preferably, the process of the present invention is carried out without substantially having a halide such as an iodide. The term 'substantially' refers to the content of the reaction gas (dimethyl ether and carbon dioxide) and the halide (for example, iodide) of the catalyst, which is less than 500 ppm, preferably less than 100 ppm.

The main product of the process is methyl acetate, but it also produces a small amount of acetic acid. The methyl acetate produced by the process of the present invention can be removed in the form of steam and then concentrated to a liquid.

The methyl acetate can be recovered and sold in this form, or it can be directed to other chemical processes. When the methyl acetate is recovered from the carbonylation reaction product, part or all of it may be hydrolyzed to form acetic acid. Alternatively, the entire carbonylation reaction product can be subjected to a hydrolysis step, after which acetic acid is separated. This hydrolysis can be carried out using known techniques such as reactive distillation in the presence of an acid catalyst.

The process can be operated in a continuous or batch process. Preferably, it is operated in a continuous process.

The invention will now be illustrated by reference to the following examples.

Example 1

This example demonstrates the effect of adding hydrogen to the dimethyl ether carbonylation at 180 to 300 °C.

Catalyst preparation Catalyst A-H-mordenite

The yttrium aluminum ratio is 20 mordenite (ex S d-Chemie) was extruded at 250 bar with a powtec wheel press for a total of 4 cycles, then pulverized and sieved to give a fraction having a particle size of 125 to 160 microns. 2.5 g of this mordenite was impregnated with 2250 μL of deionized water. After the impregnation, the mordenite was then placed on a shaker for 1 hour under ambient conditions. After this shaking, the mordenite was transferred to a forced convection oven (ambient air) and heated to 80 ° C for 20 hours. After the drying step, the mordenite was at a temperature of 500 ° C in a muffle oven (oven volume = 12 L) at a temperature of 1 L/min at a gas flow rate of 1 L/min. The slope of the minute was air calcined to a temperature of 120 ° C and maintained at 120 ° C for 180 minutes, then the temperature was increased to 500 ° C at 1 ° C / minute and maintained at 500 ° C for 180 minutes. The mordenite was then cooled to room temperature in the muffle furnace at a flow rate of (dry) gas of 1 L/min. The mordenite was gradually pushed through a 160 μm sieve to obtain particles having a size ranging from 125 to 160 μm.

Catalyst B-loaded Ag mordenite

The yttrium aluminum ratio is 20 mordenite (ex S d-Chemie) was extruded at 250 bar with a powtec wheel press for a total of 4 cycles, then pulverized and sieved to give a fraction having a particle size of 125 to 160 microns. The extruded mordenite was treated with a silver (I) nitrate solution to obtain 55 mol% silver relative to the aluminum system. The LOI (loss on ignition, 600 ° C) (typically 10-20%, in this case 18.0%) of the mordenite is measured to calculate the moisture absorbed on the mordenite to determine the desired platinum. The amount of metal solution required for loading. 426 μL of a 4 mol/L silver nitrate (I) solution dissolved in 1824 μL of deionized H ₂ O was prepared and impregnated with 2.5 g of the mordenite after the impregnation, the mordenite then Place on a shaker for 1 hour under ambient conditions. After this shaking action, the silver loaded mordenite was transferred to a forced convection oven (under ambient air) and heated to 80 °C for 20 hours. After the drying step, the silver-loaded mordenite was placed in a muffle oven (oven volume = 12 L) at a temperature of 500 ° C under air (gas flow rate of 1 L/min) The air was calcined to a temperature of 120 ° C at a slope of 1 ° C / min, maintained at 120 ° C for 180 minutes, and then the temperature was increased to 500 ° C at 1 ° C / min, maintained at 500 ° C for 180 minutes. The silver-loaded mordenite was then cooled to room temperature in the muffle furnace at a gas flow rate of 1 L/min (dry). The silver-loaded mordenite was gradually pushed through a 160 μm sieve and sieved to obtain particles having a size ranging from 125 to 160 μm.

Carbonylation of dimethyl ether

Dimethyl ether is carbonylated with carbon monoxide in the presence of each of catalysts A and B and in the presence of hydrogen. This experiment is for example in the type of pressurized continuous reactor unit comprising 16 identical reactors as described in WO 2005063372. A 5 cm (approximately) talc bed having a sieve size of 100-350 μm was placed in the catalyst holders before the catalyst was loaded into the reactor. A 5 cm (approximately) section of corundum having a sieve size of 125-160 μm is placed on top of the talc bed. 1.0 ml of catalyst was placed on the top of the corundum bed. The catalyst was covered with a corundum bed having a particle size of 125-160 μm. A 5 cm (approximately) section of talc having a sieve size of 100-350 μm is placed on top of the corundum bed. Each section is tapped or shaken to obtain a stable bed and a predetermined catalyst section starting height. The catalyst was then pressurized to 30 bar with N ₂ at a flow rate of 4 L/h. The catalyst was then heated at 0.5 ° C/min to a maintained temperature of 220 ° C and maintained at this temperature for 3 hours. The temperature was then rapidly ramped up to 400 ° C at 0.5 ° C/min and continued for another 3 hours. At this point, catalyst activation was deemed to have been completed and the temperature of the reactor was reduced to 180 °C. After the temperature reached 180 ° C, the gas feed was switched to a mixture of carbon monoxide, nitrogen and dimethyl ether (DME) with a CO/N ₂ /DME ratio of 78/20/2 at a flow rate of 4 l/h. . Dimethyl ether was fed at 0.08 l/h in steam to give a CO/N ₂ /DME molar ratio of 78/20/2 in the total feed. In addition to this, the N ₂ system was introduced at a variable flow rate of 0-50 ml/min to balance the pressure oscillation between the 16 reactor outlets. The outlet stream from the reactor is passed to a gas chromatography analyzer to determine the concentration of the reactants and the carbonylation product. The reaction was allowed to continue at 180 ° C, 30 bar, a gas hourly space velocity (GHSV) of 4000/h, and a molar ratio of CO/N ₂ /DME of 78/20/2. 24 hours. After a total reaction time of 24 hrs, the CO/N ₂ /DME feed system was switched to CO/H ₂ /DME. The reaction was allowed to be at a gas hourly space velocity (GHSV) of 180 ° C, 30 bar, and a system of 4000 / h, with a series of 78/20/2 CO/H ₂ /DME molar ratio. Continue for another 24 hours. After a total reaction time of 48 hrs, the temperature was increased from 180 °C to 240 °C. The reaction was allowed to be at a gas hourly space velocity (GHSV) of 240 ° C, 30 bar, a series of 4000 / h, with a series of 78 / ₂₀ / ₂ CO / H ₂ / DME molar ratio Continue for another 12 hours. After a total reaction time of 61 hrs, the temperature was increased from 240 ° C to 300 ° C. The reaction was allowed to be at a gas hourly space velocity (GHSV) of 300 ° C, 30 bar, and a system of 4000 / h, with a series of 78/20/2 CO/H ₂ /DME molar ratio. Continue for another 23 hours. The results of the carbonylation experiments for each of these catalysts are shown in Figure 1.

Figure 1 illustrates the effect of the addition of hydrogen in the carbonylation reaction on the rate of formation of the methyl acetate product. It is confirmed in the results shown in Fig. 1 that the presence of hydrogen has no/less influence on the carbonylation reaction at a lower temperature (180 ° C), but at a higher temperature (240 ° C and higher) It does have an impact.

Examples 2 and 3

These examples demonstrate this by (i) initially performing the carbonylation in the presence of hydrogen and then in the absence of hydrogen, and (ii) initially performing the carbonylation in the absence of hydrogen and then in the presence of hydrogen. The effect of hydrogen on the carbonylation of dimethyl ether at temperatures ranging from 180 to 350 °C.

Catalyst preparation Catalyst C-H-mordenite

The yttrium aluminum ratio is 20 H-mordenite (H-MOR) (ex S d-Chemie) was calcined in a stable air environment in a muffle oven (oven volume = 18 L) using the following temperature schedule. The temperature was increased from room temperature to 90 ° C at a slope of 3 ° C/min and maintained at this temperature for 2 hours. The temperature system was then increased from 90 ° C to 110 ° C at a slope of 1 ° C/min and maintained at this temperature for 2 hours. The temperature system was then increased from 110 ° C to 500 ° C at a slope of 5 ° C / min and maintained at this temperature for 6 hours before being allowed to cool to room temperature. The mordenite was then extruded at 12 metric tons using a Specac press in a 33 mm stamping die and then pulverized and sieved to give a particle size of 212 to 335 microns.

Catalyst D-Cu-mordenite-Cu(55)-MOR

The ratio of yttrium aluminum is 20 H-mordenite (ex S d-Chemie) (80 g) was placed in a 500 mL round bottom flask along with 14.29 g of copper (II) nitrate hemihydrate (98% ACS) and a stir bar. A sufficient amount of deionized water (about 100 ml) was then added to the flask to give a thick slurry. The top of the flask was then loosely capped and the flask was stirred and allowed to stand overnight. The copper-loaded mordenite was then dried in a rotary oven under reduced pressure using a rotary evaporator before drying at 90 ° C for 12 hours in an oven. The mordenite was then calcined in a stable air environment in a muffle furnace (oven volume = 18 L) using the following temperature schedule. The temperature was increased from room temperature to 90 ° C at a slope of 3 ° C/min and maintained at this temperature for 2 hours. The temperature system was then increased from 90 ° C to 110 ° C at a slope of 1 ° C/min and maintained at this temperature for 2 hours. The temperature system was then increased from 110 ° C to 500 ° C at a slope of 5 ° C / min and maintained at this temperature for 6 hours before being allowed to cool to room temperature. The mordenite was then extruded at 12 metric tons using a Specac press in a 33 mm stamping die and then pulverized and sieved to give a particle size of 212 to 335 microns. The mordenite has a copper loading of about 55 mol% relative to the aluminum contained in the mordenite.

Catalyst E-Ag-mordenite-Ag(55)-MOR

Catalyst E was prepared in the same manner as Catalyst D except that silver nitrate (99+% ACS) (10.47 g for 80 g of mordenite) was used instead of copper (II) nitrate. The resulting mordenite system has a silver loading of about 55 mole % relative to the aluminum system.

Catalyst F-CuPt-Mordenite-KCu(55)Pt(1)-MOR

In addition to the use of 0.20 g of potassium tetranitroplatinate (ex Aldrich) instead of copper (II) nitrate, and using catalyst D itself as the zeolite matrix rather than H-mordenite, catalyst F is based on the catalyst used to prepare catalyst D. The method is prepared. The mordenite produced had a copper loading of 55 mol% and a platinum loading of 1 mol% relative to the aluminum contained in the mordenite.

Example 2 - Carbonylation of Dimethyl Ether in the Presence of Initial Hydrogen

The dimethyl ether is carbonylated in the presence of a temperature of from 180 to 350 ° C and a pressure of 70 barg in the presence of each of the catalysts C to F. Such experiments are carried out in a pressurized continuous reaction unit of the type described, for example, in WO2006107187, comprising 60 identical parallel isothermal co-flow tube reactors. The reactor was framed to form four blocks with 15 reactors, each with an independent temperature control. Only blocks 1 through 3 are used in this example. In each reaction tube, 50 microliters of catalyst (which was designed to produce a GHSV of 4000 h ^-1 ) was loaded onto a metal frit having a pore size of 20 microns. The catalyst was heated to 100 ° C at a temperature of 5 ° C / min and maintained at this temperature under the conditions of an atmospheric pressure of 98.6 mol % N ₂ and 1.4 mol % He at a flow rate of 3.4 ml/min. 1 hour. The reactor was then pressurized to 70 barg and the system was maintained under this condition for 1 hour. The gas feed was then switched to 63.1 mol% carbon monoxide, 15.8 mol% hydrogen, 19.7 mol% nitrogen, and 1.4 mol% He at a flow rate of 3.4 ml/min, and the system was The slope of 3 ° C / min was used to heat to a temperature of 300 ° C. The system was then maintained under this condition for 3 hours. After that, the temperatures of the blocks 1 to 3 were adjusted to 180, 300 and 350 ° C, respectively, and the system was stabilized for 10 minutes. At this point, the catalyst activation was deemed to have been completed, and the gas feed was converted to a flow rate of 3.4 ml/min of 63.1 mol% carbon monoxide, 15.8 mol% hydrogen, and 14.8 mol% nitrogen. 1.4 mole % of 莫 and 4.9 mole % of dimethyl ether. The reaction was carried out before the gas feed was converted to a flow rate of 3.4 ml/min of 63.1 mol% carbon monoxide, 30.6 mol% nitrogen, 1.4 mol% bismuth, and 4.9 mol% dimethyl ether. It is allowed to continue for about 85 hours under these conditions. These conditions were maintained for approximately 28 hours. The outlet flow from the reactor is conducted to two gas chromatograph analyzers; one has three columns each equipped with a thermal detector (Molecular sieve 5A, Porapak) Q and CP-Wax-52) Varian 4900 micr GC color layer analyzer, and an Interscience Trace with two columns (CP-Sil 5 and CP-Wax 52) each equipped with a flame ionization detector GC chromatography analyzer. The results of Example 2 are shown in Figures 2 through 4. Figures 2 to 4 respectively illustrate the effects of hydrogen at 180 ° C, 300 ° C and 350 ° C. In these figures, productivity (STY _acetyls ) is defined as the STY for the production of AcOH plus the STY for the production of MeOAc and multiplied by MW _AcOH / MW _MeOAc .

Example 3 - Dimethyl ether carbonylation in the absence of initial hydrogen

The gas feed was converted to 63.1 mol% of one carbon oxide after the temperature of blocks 1 to 3 was adjusted to 180, 300 and 350 ° C, respectively, after the system was maintained at a temperature of 300 ° C for 3 hours. , 35.5 % of nitrogen and 1.4% by mole, and the system is allowed to stabilize for up to 10 minutes, the temperature of the dimethyl ether is in the range of 180 to 350 ° C and a pressure of 70 barg, The experimental procedure described in Example 2 above was followed by carbonylation. At this point, the catalyst activation was deemed to have been completed and the gas feed was converted to a flow rate of 3.4 ml/min of 63.1 mol% carbon monoxide, 30.6 mol% nitrogen, 1.4 mol% 氦And 4.9 mol% of dimethyl ether. The gas feed was converted to a flow rate of 3.4 ml/min of 63.1 mol% carbon monoxide, 15.8 mol% hydrogen, 14.8 mol% nitrogen, 1.4 mol% 氦, and 4.9 mol%. The reaction was allowed to continue for about 85 hours under these conditions prior to dimethyl ether. These conditions were maintained for approximately 28 hours. The results of Example 3 are shown in Figures 2 through 4.

Figure 2 further demonstrates the teachings of the prior art that the presence of hydrogen at a lower temperature has only a small amount/no effect on productivity. However, as clearly illustrated in Figures 3 and 4, at higher temperatures, in dimethyl The presence of hydrogen in the carbonylation of the ether provides an improved effect in productivity. From Figure 4, it can be seen that hydrogen is a major factor in productivity when the zeolite catalyst is loaded into a metal.

Examples 4 to 9

These examples illustrate the effect of carbonylation of dimethyl ether under different hydrogen partial pressures.

Catalyst preparation Catalyst G-Cu-mordenite-Cu(55)-MOR

In addition to 17.8 g instead of 14.29 g of copper nitrate dihydrate (98% ACS, ex Aldrich) was used to load 100 g of yttrium aluminum with a ratio of 20 to H-mordenite (ex S In addition to d-Chemie), Catalyst G was prepared in the same manner as Catalyst D, and the copper-loaded mordenite obtained was calcined at 500 ° C for 16 hours.

Catalyst H-Ag-mordenite-Ag(42)-MOR

In addition to 5.06 g instead of 10.47 g of silver nitrate (99+% ACS, ex Aldrich) was used to load up to 50.6 g of H-mordenite with a ratio of yttrium aluminum of 20 (ex S In addition to d-Chemie), Catalyst G was prepared in the same manner as Catalyst D, and the copper-loaded mordenite obtained was calcined at 500 ° C for 16 hours.

Catalyst I-H-mordenite

The ratio of bismuth to aluminum is 20 H-mordenite (ex S d-Chemie) was extruded in a 33 mm stamping die holder at 12 metric tons using a Specac press and then comminuted and sieved to give a particle size of 212 to 335 microns.

Catalyst D, Catalyst E and Catalyst C were used in Examples 4, 6 and 8, respectively, except that each catalyst was sieved to a particle size of 500 to 1000 microns after calcination. Catalyst G, Catalyst H and Catalyst I were used in Examples 5, 7 and 9, respectively.

Example 4-Dimethyl Ether Carbonylation

A stainless steel reaction tube was filled with 2.0 ml of Catalyst D and covered with 1 ml of glass powder. The reactor tubing is mounted in a downstream support of a stainless steel U-tube. The upstream support of the U-shaped tube is filled with glass frit. The catalyst in the reactor/U-tube was heated from ambient temperature to a temperature of 46.7 barg and a flow rate of 125 ml/min NTP (20 ° C, 1 atm) at a gradient of 3 ° C/min. 100 ° C and maintained under this condition for 18 h. The catalyst was then subjected to a mixture of carbon monoxide, hydrogen and hydrazine (carbon monoxide 48.4 vol%, hydrogen 48.4 vol%, cesium 3.2 vol%) at a pressure of 46.7 barg and a flow rate of 202 ml/min NTP (20 ° C, 1 atm). The slope of 3 ° C / min was heated from 100 ° C to 300 ° C and maintained under this condition for 2 hours. Dimethyl ether (BOC, >99.99%) is then fed in liquid form from a high pressure syringe pump to the reactor on the glass frit in the upstream support of the U-tube where it vaporizes and passes through the catalyst Previously mixed with the gas feed. The liquid dimethyl ether was fed at a rate of 0.0185 ml/min while cooling the syringe to 5 °C. The reactor pressure is regulated by a pressure control valve located downstream of the reactor, and the temperature of the reactor effluent gas is maintained at at least 150 °C. The effluent gas system of the reactor is sheared down to ambient pressure by the pressure control valve. The effluent gas system is cooled to 60 ° C before the effluent gas stream is conducted to a mass spectrometer and gas phase chromatography analyzer for analysis. The kettle is separated by a gas to collect any non-volatile material. Gas phase chromatography analysis of the methyl acetate and acetamidine-based products from the reactor, the unit time time yield (STY) of the acetic acid product is corresponding to the acetic acid produced per liter of catalyst per hour. The total amount of methyl ester and acetic acid is expressed as the molar equivalent of the ethyl oxime product.

Examples 5 to 9

Example 4 was repeated using each of the catalysts G, E, H, C, and I. The flow rates of dimethyl ether, carbon monoxide, helium and hydrogen (expressed as the volume of gas under NTP), and the total pressure used in each example are shown in Table 1. The calculated partial pressure of the feed component and the unit space time yield (STY) of the acetamidine-based product are also shown in Table 1.

It can be seen from the comparison of Examples 4 and 5 that increasing the partial pressure of hydrogen will result in a substantial increase in the product STY. In addition, increasing the partial pressure of hydrogen reduces the rate of loss of catalytic activity. In Example 4 (at higher hydrogen partial pressures), the catalytic activity of the product stream after 210 hours is 63% of the catalytic activity after 20 hours, but in Example 5 (at a lower hydrogen partial pressure) In the lower part, the catalytic activity of the product stream after 210 hours was only 36% of the catalytic activity after 20 hours. Similar effects can also be found in comparing the results of Examples 6 and 7 and the results of Examples 8 and 9.

Figure 1 illustrates the effect of the addition of hydrogen in the carbonylation reaction on the rate of formation of the methyl acetate product.

Figure 2 illustrates the effect of hydrogen on the space time yield of the acetamidine-based product at a temperature of 180 °C.

Figure 3 illustrates the effect of hydrogen on the space time yield of the ethylene-based product at a temperature of 300 °C.

Figure 4 illustrates the effect of hydrogen on the space time yield of the acetamidine-based product at a temperature of 350 °C.

Claims (37)

A process for the production of methyl acetate comprising carbonylating a dimethyl ether feed with carbon monoxide in the substantial absence of water, in the presence of a zeolite catalyst effective for the carbonylation Wherein the carbonylation is carried out at a temperature in the range of from 240 ° C to 350 ° C and in the presence of hydrogen. The method of claim 1, wherein the temperature is in the range of from 275 ° C to 350 ° C. The method of claim 1 or 2, wherein the carbon monoxide: hydrogen molar ratio is in the range of 1:3 to 15:1. The method of claim 3, wherein the carbon monoxide:hydrogen molar ratio is in the range of from 1:1 to 10:1. The method of claim 1 or 2, wherein the hydrogen is fed to the process in a separate feed stream. The method of claim 1 or 2, wherein the hydrogen is fed to the process as a mixture of carbon monoxide and carbon monoxide. The method of claim 6, wherein the mixture of hydrogen and carbon monoxide is produced by steam reforming of a hydrocarbon or partial oxidation of a hydrocarbon. The method of claim 1 or 2, wherein the method is carried out at a hydrogen partial pressure of from 0.1 to 50 barg. The method of claim 8, wherein the method is carried out at a hydrogen partial pressure system in the range of from 3 to 30 barg. The method of claim 9, wherein the method is based on hydrogen partial pressure It is carried out in the range of 5 to 25 barg. The method of claim 1 or 2, wherein the method is carried out in a range of from 0.1 to 50 barg of a carbon monoxide partial pressure system. The method of claim 1 or 2, wherein the method is carried out at a total pressure of from 1 to 100 barg. The method of claim 12, wherein the method is carried out at a total pressure of from 10 to 100 barg. The method of claim 13, wherein the method is carried out at a total pressure of from 30 to 100 barg. The method of claim 14, wherein the method is carried out at a total pressure of from 30 to 80 barg. The method of claim 1 or 2, wherein the carbon monoxide has a molar ratio of 1:1 to 99:1 over the upper dimethyl ether. The method of claim 1 or 2, wherein the dimethyl ether feed is obtained by catalytic conversion of a mixture of carbon monoxide and hydrogen on a methanol synthesis and a methanol dehydration catalyst. The method of claim 1 or 2, wherein the dimethyl ether feed comprises methanol in an amount of up to 5 wt%. The method of claim 1 or 2, wherein the zeolite is loaded with one or more metals. The method of claim 1, wherein the zeolite comprises at least one channel defined by an 8-member ring. The method of claim 20, wherein the 8-member ring channel is interconnected with at least one channel defined by a 10 and/or 12-member ring. The method of claim 20, wherein the 8-member ring channel has a window size of at least 2.5 x 3.6 angstroms. The method of claim 1 or 2, wherein the zeolite has a ratio of 矽:X ₂ O ₃ in the range of 5 to 100, wherein the X system is one selected from the group consisting of aluminum, gallium, and boron. A trivalent element of at least one of the irons. The method of claim 1 or 2, wherein the zeolite has an architectural type selected from the group consisting of MOR, FER, OFF, and GME. The method of claim 24, wherein the zeolite is selected from the group consisting of mordenite, ferrierite, potassium zeolite and sodium chabazite. The method of claim 25, wherein the mordenite is H-mordenite. The method of claim 26, wherein the mordenite is ion exchanged or otherwise loaded at least selected from the group consisting of copper, nickel, ruthenium, silver, rhodium, platinum, palladium and cobalt. a metal. The method of claim 27, wherein the mordenite is ion exchanged or otherwise loaded with a metal selected from the group consisting of copper, silver, and the like. The method of claim 27, wherein the metal is present in the mordenite in a loading amount in the range of from 1 to 200 mol% relative to aluminum. The method of claim 28, wherein the metal is present in the mordenite in a loading amount in the range of from 1 to 200 mol% relative to aluminum. The method of claim 29, wherein the metal loading is in the range of 50 to 120 mol% relative to aluminum. The method of claim 30, wherein the metal loading amount is in the range of 50 to 120 mol% relative to aluminum. The method of claim 26, wherein the framework of the mordenite comprises a mixture of boron, gallium, iron or the like. The method of claim 1 or 2, wherein the total halide content of the dimethyl ether, carbon monoxide and the zeolite catalyst is less than 500 ppm. The method of claim 1 or 2, wherein at least some of the methyl acetate product is hydrolyzed to acetic acid. The method of claim 1, wherein the carbonylation is in the range of from 275 ° C to 350 ° C in the presence of a mordenite at a total pressure of from 30 to 80 barg and Carbon monoxide: The molar ratio of hydrogen is from 1:1 to 4:1. The method of claim 1, wherein the carbonylation is carried out at a temperature ranging from 275 ° C to 350 ° C in the presence of a mordenite at a total pressure of from 30 to 80 barg and a It is carried out at a hydrogen partial pressure in the range of 5 to 25 barg.